This invention relates generally to masks for supplying breathable gas to a person, and more particularly, relates to a nasal CPAP (Continuous Positive Airway Pressure) mask particularly useful for supplying pressurized breathing gas, such as oxygen, to a person in the treatment of obstructive sleep apnea.
The prior art is replete with masks which are of many different sizes, structures and for use in many different applications. Many different full face masks covering both the nose and the mouth are known to the art, and many different nasal masks covering only the nose are known to the art. A typical mask may include a shell of relatively hard or stiff material and a seal mounted to the shell and for conforming to the contours of a person's face, surrounding the nose and/or mouth, and for engaging such contours in an air-tight or sealing engagement. Such shell and seal may be made of numerous materials known to the art and also known to the art are numerous methods and structures for mounting the seal to the shell.
As is further known to the art, such masks typically include head gear comprising a plurality of headstraps which encircle the person's head and/or neck and which are adjustable to individualize the tension applied to the mask thereby individualizing the amount of force applied to the seal so that the seal will sealingly engage different contours of the faces of different people.
As is further known, the shells of such prior art masks are provided with venting means, such as a hole or plurality of holes, for preventing the accumulation of carbon dioxide in the shell and for providing for the exiting of the person's exhaled breath. Such prior art venting can produce a noisy or turbulent air flow or jet of air which can impinge annoyingly on the mask wearer or onto nearby persons such as a sleep partner.
Accordingly, it is believed that there is a need in the art for a mask having improved venting which reduces the noise level of the vented air and which directs the vented air away from the mask wearer thereby reducing discomfort to the mask wearer and annoyance to adjacent people such as a sleep partner.
Referring more particularly to the above-noted obstructive sleep apnea treatment, typically, in the night time treatment of obstructive sleep apnea, a nasal mask is placed over a person's nose and forced into sealing engagement with the contours of the patient's face surrounding the nose by adjusting and tightening the above-noted headstraps. The mask is connected to a ventilator which supplies breathing gas to the patient for the night time obstructive sleep apnea treatment. Typically, the adjustable headstraps are mounted fixedly to the mask which requires the headstraps to be loosened or removed to free the person from the mask for movement during the night time such as going to the bathroom. Upon return and recommencement of the obstructive sleep apnea treatment, the mask must again be placed into sealing engagement with the face and the headstraps again readjusted or retightened. This loosening and re-tightening of the headstraps is known to be quite annoying.
Further, the mask, particularly the seal, must be cleaned and since, as noted, the mask is typically mounted fixedly to the headstraps, this makes cleaning more difficult than is desirable. Further, the cleaning of a mask or seal mounted fixedly to the headstraps can cause the headstraps to become wet and possibly suffer shrinkage or at least some structural or functional impairment.
Accordingly, it is believed there is a need in the art for a new and improved mask mounted removably to the adjustable headstraps which permits the mask to be removed from the headstraps during the night time, freeing the person from the mask and ventilator and permitting the person to move about while the headstraps remain on the person's head, tightened and still individually adjusted to the patient's head. It is also believed there is a need in the art for such removable mask and headstrap combination which permits the mask and seal to be cleaned separately and apart from the headstraps.
Referring again to the prior art mask seals, some prior art mask seals are comprised of thermoset silicone, closed-cell foams, molded silicone and some include a soft material interposed between two thin plastic films and which are mounted to the mask shell by different mounting techniques. These prior art seal structures are generally known to be costly to manufacture.
Accordingly, it is further believed that there is a need in the art for a new and improved mask seal which may be manufactured cost effectively and for a new and improved structure for mounting the seal to the shell.